Research was carried out on motor function in man in relation to aging and disease. With the use of a patient activity monitor worn on the non-dominant wrist in 14 healthy men for a period of 10 days, it was demonstrated that average wrist motor activity was lower in older individuals, primarily as a result of low activity during daytime hours. Sleep duration could be estimated from the analysis, and was not correlataed with age. A quantitative neurological examination was standardized in healthy men between 20 and 80 years of age, and established curves for ages related declines in coordination, speed and accuracy of movement. There was significant correlation between age and peripheral hearing sensitivity in healthy men, particularly at high frequencies, but when the effects of hearing loss due to age were taken into account, measures of speech discrimination and tympanometry were not related significantly with age. In patients with Alzheimer's, disease studies of central auditory function using the staggered spondaic word (SSW) test indicated that a unilateral deficit was associated with temporal lobe atrophy on the contralateral cerebral hemisphere, as measured with CT scans, but not with asymmetry of cerebral glucose utilization.